Air bed



FIG. 1 is a perspective view of an air bed showing my new design;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a left side elevation view thereof;

FIG. 5 is a right side elevation view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken lines depict portions of the air bed which form no part of the claimed design. 

CLAIM The ornamental design for an air bed, as shown and described. 